fix random failures, triggered by gentoo qa scripts: missing declarations (headers), assigning NULL to int or double

diff -Nur scilab-5.3.3.orig/modules/api_scilab/src/cpp/api_double.cpp scilab-5.3.3/modules/api_scilab/src/cpp/api_double.cpp
--- scilab-5.3.3.orig/modules/api_scilab/src/cpp/api_double.cpp	2012-04-16 21:18:42.000000000 +0100
+++ scilab-5.3.3/modules/api_scilab/src/cpp/api_double.cpp	2012-05-23 23:26:09.000000000 +0100
@@ -481,7 +481,7 @@
 /*--------------------------------------------------------------------------*/
 int createScalarDouble(void* _pvCtx, int _iVar, double _dblReal)
 {
-    return createCommonScalarDouble(_pvCtx, _iVar, 0, _dblReal, NULL);
+    return createCommonScalarDouble(_pvCtx, _iVar, 0, _dblReal, 0);
 }
 /*--------------------------------------------------------------------------*/
 int createScalarComplexDouble(void* _pvCtx, int _iVar, double _dblReal, double _dblImg)
diff -Nur scilab-5.3.3.orig/modules/api_scilab/src/cpp/api_list.cpp scilab-5.3.3/modules/api_scilab/src/cpp/api_list.cpp
--- scilab-5.3.3.orig/modules/api_scilab/src/cpp/api_list.cpp	2012-04-16 21:18:42.000000000 +0100
+++ scilab-5.3.3/modules/api_scilab/src/cpp/api_list.cpp	2012-05-23 23:23:22.000000000 +0100
@@ -1133,7 +1133,7 @@
 	SciErr sciErr; sciErr.iErr = 0; sciErr.iMsgCount = 0;
 	int* piAddr				= NULL;
 	int* piRoot				= NULL;
-	int iNbItem				= NULL;
+	int iNbItem				= 0;
 
 	if(_piParent == NULL)
 	{
@@ -1329,7 +1329,7 @@
 	SciErr sciErr; sciErr.iErr = 0; sciErr.iMsgCount = 0;
 	int* piAddr				= NULL;
 	int* piRoot				= NULL;
-	int iNbItem				= NULL;
+	int iNbItem				= 0;
 	int* piBool				= NULL;
 
 
@@ -1577,7 +1577,7 @@
 	SciErr sciErr; sciErr.iErr = 0; sciErr.iMsgCount = 0;
 	int* piAddr				= NULL;
 	int* piRoot				= NULL;
-	int iNbItem				= NULL;
+	int iNbItem				= 0;
 
 	if(_piParent == NULL)
 	{
diff -Nur scilab-5.3.3.orig/modules/core/src/c/csignal.c scilab-5.3.3/modules/core/src/c/csignal.c
--- scilab-5.3.3.orig/modules/core/src/c/csignal.c	2012-04-16 21:18:43.000000000 +0100
+++ scilab-5.3.3/modules/core/src/c/csignal.c	2012-05-23 23:18:19.000000000 +0100
@@ -11,6 +11,7 @@
  *
  */
 #include <stdio.h>
+#include <string.h>
 #include "banier.h"
 #include "csignal.h"
 #include "sigbas.h"
diff -Nur scilab-5.3.3.orig/modules/functions/src/c/getmacroslist.c scilab-5.3.3/modules/functions/src/c/getmacroslist.c
--- scilab-5.3.3.orig/modules/functions/src/c/getmacroslist.c	2012-04-16 21:18:41.000000000 +0100
+++ scilab-5.3.3/modules/functions/src/c/getmacroslist.c	2012-05-23 23:18:38.000000000 +0100
@@ -11,6 +11,7 @@
  *
  */
 #include <stdlib.h>
+#include <string.h>
 #include "api_scilab.h"
 #include "sci_types.h"
 #include "getmacroslist.h"
diff -Nur scilab-5.3.3.orig/modules/localization/src/c/charEncoding.c scilab-5.3.3/modules/localization/src/c/charEncoding.c
--- scilab-5.3.3.orig/modules/localization/src/c/charEncoding.c	2012-04-16 21:18:43.000000000 +0100
+++ scilab-5.3.3/modules/localization/src/c/charEncoding.c	2012-05-23 23:16:17.000000000 +0100
@@ -16,6 +16,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <locale.h>
+#include <wctype.h>
 #include "charEncoding.h"
 #include "MALLOC.h"
 /*--------------------------------------------------------------------------*/
diff -Nur scilab-5.3.3.orig/modules/matio/src/c/CreateCharVariable.c scilab-5.3.3/modules/matio/src/c/CreateCharVariable.c
--- scilab-5.3.3.orig/modules/matio/src/c/CreateCharVariable.c	2012-04-16 21:18:43.000000000 +0100
+++ scilab-5.3.3/modules/matio/src/c/CreateCharVariable.c	2012-05-23 23:19:36.000000000 +0100
@@ -11,6 +11,7 @@
  *
  */
 
+#include <string.h>
 #include "api_scilab.h"
 #include "CreateMatlabVariable.h"
 #include "freeArrayOfString.h"
--- scilab-5.3.3.orig/modules/graphics/src/c/getHandleProperty/set_log_flags_property.c	2012-04-16 21:18:41.000000000 +0100
+++ scilab-5.3.3/modules/graphics/src/c/getHandleProperty/set_log_flags_property.c	2012-05-24 20:54:16.000000000 +0100
@@ -18,6 +18,7 @@
 /*        a handle                                                        */
 /*------------------------------------------------------------------------*/
 #include <string.h>
+#define _GNU_SOURCE
 #include <math.h>
 #include "setHandleProperty.h"
 #include "SetProperty.h"